Peelable envelope for sterile articles

ABSTRACT

A sterilizable envelope for retaining articles before, during and after sterilization and for maintaining sterility of the contents for extended periods of time. One wall of the envelope is made of an opaque material, such as paper, and the other wall is a transparent material, such as a plastic film, these materials being sealed together around the periphery of the envelope. A portion of the periphery of the envelope is left open for receiving the article to be stored, whereupon the seal may be completed for subsequent sterilization and storage. Another portion of the periphery of the envelope is configured for easy opening by separating a portion of the two walls to expose the enclosed sterile article.

United States Patent 1 3,604,616

[72] Inventor Edward E. Greif [56] References Cited Philadelphia, UNITED STATES PATENTS P g g i 3,152,694 10/1964 Nashed etal. 206 63.2 52: d 197] 3,332,549 7/1967 Powell 206/63.2 3,410,395 111968 511 206 63.2 [73] Assignee Edward Weck8zCompany, Inc. I e ers I Long I land Cit NY, Primary Examiner-David M. Bockenek Attorney-Joseph Weingarten ABSTRACT: A sterilizable envelope for retaining articles before, during and after sterilization and for maintaining sterility of the contents for extended periods of time. One wall of the envelope is made of an opaque material, such as paper, and

[54] STERILE ARTICLES the other wall is a transparent material, such as a plastic film, these materials being sealed together around the periphery of [52] US. Cl 229/55, the envelope. A portion of the periphery of the envelope is left 206/63.2 R, 206/56 R open for receiving the article to be stored, whereupon the seal [51 Int. Cl ..B65d 33/02. may be completed for subsequent sterilization and storage. A6lb 19/02 Another portion of the periphery of the envelope is configured [50] Field of Search 229/55, 48 for easy opening by separating a portion of the two walls to ex- T, 3.5, 62, 66; 206/63.2, 56 A pose the enclosed sterile article.

,4 1: \II I i.--l4 1 I I l I I l I 1 1 I I l I I 1 l I I l i l 1 1 I I PATENTEU SEPI 41am INVI'IN'I'UR w EDWARD E. GREIF PEELABLE ENVELOPE FOR STERILE ARTICLES FIELD OF THE INVENTION This invention relates in general to packaging techniques and, more particularly, concerns a peel-open sterilizable envelope for retaining articles before, during, and after sterilization and for maintaining sterility of the enclosed articles for a substantial length of time.

DISCUSSION OF THE PRIOR ART It is common practice to package and store surgical instruments, surgeons gloves, dressings, sutures and like articles in sealed envelopes in order to retain these articles in sterile condition until they are used. In the commercial application of this practice, a sterilized article or an article to be sterilized is often furnished by the manufacturer thereof in a sealed envelope capable of withstanding autoclave or gas sterilization. When the article is to be used, the envelope is opened by some appropriate method which is intended to expose the enclosed article for use without causing it to become contaminated by contact with the external portions of the package. Various envelope materials have been used and, while paper is frequently employed because of its ease of fabrication, its economy and its ability to permit sterilization of enclosed articles, such packages have at times been made of plastic, metal foil, metal foil laminates or some combination of these materials.

Many prior packaging techniques give rise to certain problems. If no portion of the package is transparent, care must be exercised to ensure that each package is properly labeled as to its contents. On the other hand, some wholly transparent plastic packages have no provision for affixing the date of sterilization of the contents, which is important in maintaining strict quality control over stored sterilized articles. Another characteristic of many plastics is that, after sealing, such a package is often difficult to open without contaminating the contents. Another significant problem common to many of the prior packages which are opened by separating two layers which are sealed together is that the layers often tear instead of at their bonding point with the result the package may be only partially opened or not opened at all while a small portion of one wall of the package is torn away.

SUMMARY OF THE INVENTION Broadly speaking the present invention provides an envelope having one wall preferably made of a dual-layered paper and the other wall made of a transparent plastic film, such as nylon. Both the paper and the plastic walls allow the contents of the envelope to be sterilized after the envelope has been filled and sealed. Provisions are made for easily opening the envelope by separating the plastic from the paper so that the envelope always opens in such a way as to expose the article contained therein for easy accessibility to the user.

A particularly important feature of the envelope of this invention is that the user, such as a doctor, nurse, or packager of medical and surgical supplies, may place any desired article into the envelope and seal it, after which the thus-completed package and its contents may be sterilized by conventional means.

With one side of the envelope being transparent, the identity of the contents is easily ascertained by visual inspection. The other side of the envelope, being made of paper, provides a surface for imprinting such words and symbols as desired by the manufacturer or user and for recording information such as the date of sterilization.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of a preferred embodiment of an envelope constructed according to the principles of this invention;

FIG. 2 is a perspective view of the envelope of FIG. 1 being filled through its open end;

FIG. 3 is a perspective view of the envelope of FIG. 2 after the normally open end has been sealed;

FIG. 4 shows the envelope of FIG. 3 being opened to provide access to the article enclosed therein;

FIG. 5 is an enlarged, broken away perspective view of a portion of one side of the envelope of FIG. 1; and

FIG. 6 is a partial view of a second preferred embodiment of the envelope of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference now to the drawing, and particularly to FIGS. 1 through 5 thereof, there is shown an envelope, designated generally by reference numeral 11, having a rear wall 12 and a front wall 13. The front wall is sealed to the rear wall at localized areas of the envelope to form the elongated U-shaped seal 14 as indicated in the drawing by dotted lines around the periphery of the envelope adjacent the edges thereof. In order to facilitate opening the envelope after it has been filled and sealed, the seal at top end 15 of the envelope is chevron shaped to provide corners of the walls which are easily separated. The envelope of this invention is formed with bottom end 16 open in order to allow articles to be inserted before the envelope is completely sealed.

There are several characteristics which walls 12 and 13 should have in order that envelope 11 have all of the desired features. For example, they should be flexible yet have sufficient strength to allow envelopes containing odd-shaped articles to be safely handled and stored while being capable of withstanding the conditions of sterilization. Furthermore, the walls of the envelope should be permeable to steam and sterilizing gas while at the same time being substantially impervious to dust and bacteria. It is desired that one wall or a portion thereof be adapted to be imprinted with appropriate legends and be capable of being written upon for such purposes as recording the date of sterilization. The other wall, on the other hand, should be transparent so that the contents of the envelope may be readily identified upon visual inspection.

The walls of the envelope may be sealed together in any desired manner which provides a positive, semipermanent, bacteria and dust-free seal which is capable of withstanding sterilization temperatures without deterioration of the quality of the seal. An adhesive may be used or the walls may be mutually heat scalable. Whatever the manner of sealing, this invention is directed to the situation where the seal is so positive that the walls may be separated only by stripping of a small portion of one of the walls at the seal line. This would normally mean that the sealing material had penetrated a fraction of the depth of one wall and does not itself readily separate from either of the walls at the sealed zones. The specific example described is concerned with a wall of one material being heat scalable to the other wall which is a different material but it should be understood that the principles of the invention apply equally well to envelopes sealed by adhesive means and which use similar materials adhered together.

Certain thermoplastic films, such as nylon, have been found to satisfy all of the above desired characteristics for wall 13. Polyethylene is also suitable, but its use is generally limited to gas sterilization. Material such as sterilizable Claremont kraft paper is among those which have been found to have the necessary properties for rear wall 12. A relatively strong bond is formed when heat is applied to the nylon to cause it to soften and flow into the pores of the paper. When the heat is removed, the envelope may be opened only by separating the two walls, whereupon that portion of thickness of the paper which is impregnated with nylon will be stripped away from the remainder of rear wall I2.

It has been found that due to inherent variations in the thickness of kraft paper and normal variations in the depth of penetration of nylon into the paper, a single sheet of paper has not been fully satisfactory for rear wall 12. Where the paper is thin or the nylon penetration deeper than normal, or both, the paper may tear through when an attempt is made to open the envelope, This results in a partially opened package or one that fails completely to open in the normal manner.

This invention, the essence of which is shown in FIG. 5, provides an envelope having all of the desired properties and which may be opened easily and positively. Rear wall 12 is comprised of two layers of paper; a relatively thick layer 17, and a relatively thin layer 18. Layers 17 and 18 are formed together and mechanically bonded at the paper mill when the paper is made without the aid of any adhesive substance. By passing damp paper in its formative stage in two layers between rollers at the proper pressure and temperature, the layers are mechanically bonded to effectively form a unitary sheet which remains in that form until a force is properly applied to separate the layers. This invention is not concerned with the method of manufacturing the paper, and more detailed description of this known process is not necessary here.

When nylon sheet 13 is heat sealed to paper rear wall 12, a small portion of the plastic enters the pores of the paper as shown at 19 in FIG. 5, and may, indeed, penetrate the entire depth of layer 18. However, when the envelope is opened by separating the layers commencing at chevron 21, as shown in FIG. 4, the portion of nylon impregnated paper layer 18 which is part of the sealed area 14 is readily separated from paper layer 17 and at the same time is ruptured from the remainder of paper layer 18 which remains firmly bonded to layer 17. It is thus apparent that only the area of layer 18 which has been penetrated by the nylon, that is, seal area 14, is removed from rear wall 12 of the envelope. While not necessary to the concept of this invention, it has been found that proper separation of front wall 13 from rear wall 12 is facilitated when the grain of layer 17 extends transversely across the envelope and the grain of layer 18 extends longitudinally of the envelope. In that way there is no danger of tearing layer 17, while layer 18 is easily torn at the edges of longitudinal heat seal lines 14 and the heat-sealed portion is stripped from layer 17 to which it is mechanically bonded. Thus, even if the nylon should penetrate entirely through layer 18 and slightly into layer 17, the separation would still readily occur at or just below the boundary between the two layers. In any event, the nylon penetration would not be sufficiently deep in layer 17 to cause that layer to tear through as might occur with a single paper layer.

Although the use of seal chevrons, such as 21, permits the top corners of the facing walls of the envelope to be easily separated to start peeling the envelope open as shown in FIG. 4, it is also desirable to make one wall slightly shorter than the other. This allows the longer wall to be readily bent away from the other wall so that both may be grasped for opening purposes. When the walls of the envelope have been peeled apart for part or all of the length of the envelope, the enclosed article may be readily removed in any appropriate way. In this regard, it is well to note that the entire interior of envelope ll inward of the heat-sealed areas 14 is sterile when the envelope is opened, so that the article may be removed without any danger of coming contact with external surfaces which may have become contaminated.

A relatively wide range of weights of paper and thicknesses of plastic film may be used for envelope 11, but the preferable dimensions are: layer 17 a kraft paper having a weight range of 27 to 33 pounds; layer 18 a kraft paper having a weight ranging between 3 and 7 pounds; and plastic front wall 13 a nylon film having a thickness ranging between 0.0005 inch and 0.005 inch. It is entirely possible that variations from the above preferred dimensions and materials may be made in constructing envelopes having the desired characteristics. The only requirement is that layer 18 be substantially thinner than layer 17 and that plastic front wall 13 be capable, in response to the application of heat, of penetrating to a substantial depth in layer 18 to achieve a secure seal. The fact that thickness variations may occur both in layers 17 and 18 and in the depth of penetration of the plastic into the paper layers does not adversely affect any of the characteristics of this envelope.

FIG. 6 shows an alternate preferred embodiment for the envelope of this invention. Envelope 22 is formed with an offset chevron seal 23 which may be preferred by some users over the centered chevron of FIG. 1. This configuration provides two differently shaped unsealed facing comer flaps which may be separated for purposes of opening the envelope.

For optimal usefulness, the envelope described herein must be easily scalable after an article has been inserted so that it may be filled and sealed on the job" if desired or by a packaging company if it intends to provide prepackaged medical and surgical articles. A relatively inexpensive device which will properly heat seal end 16 of the envelope is an Audion lmpulse Sealer made for Packaging Aids Corporation of New York City. With this device at hand, a nurse, after thoroughly cleaning surgical instruments, may insert them into individual envelopes, heat seal each envelope, and place a number of the sealed packages into a sterilizer. When the packages are properly sterilized, the contents are fully protected and their sterility maintained by the sealed envelope during subsequent handling and storage. The thus-sorted articles are then ready for use at a later time without further processing.

Having described preferred embodiments of the invention, various modifications may be made by those skilled in the art which are within the scope of the invention described herein. For example, the end of the envelope to be opened need not have a chevron-shaped seal but may have only one corner where the seal line is displaced inwardly.

What is claimed is:

1. An envelope for enclosing and retaining articles before, during and after sterilization, comprising:

a unitary first wall of first flexible sheet material comprising a first layer of said first material and a second layer of said first material, said layers being mechanically bonded together; and

a second wall of second flexible sheet material being dimensionally similar to said first wall;

said second wall being sealed to said first wall around three sides of the periphery thereof to form said envelope having one end open, said seal being in the form of a relatively narrow band.

2. The envelope of claim 1 wherein:

said second layer of said first flexible sheet material is thin compared with said first layer and said second wall is arranged in facing relation with and sealed to said second layer.

3. The envelope of claim 2, wherein:

said seal at the other end of said envelope is displaced inwardly from at least one corner thereof to permit the confronting corners of said walls to be freely separated.

4. The envelope of claim 1, wherein:

said sealed areas of said envelope being capable of withstanding sterilization temperatures without deterioration of the seal quality.

5. The envelope of claim 2, wherein:

said first and second layers comprising said first wall are paper and said second wall is a thermoplastic film capable of being heat sealed to said first wall.

6. The envelope of claim 4, wherein,

said second wall is nylon film.

7. The envelope of claim 3, wherein:

the open end of said envelope may be heat sealed to close the interior of said envelope.

8. The envelope of claim 7, wherein:

said envelope may be opened by forcibly pulling said second wall from said first wall, wherein said second layer in the vicinity of said seal separates from said first layer and is ruptured from the remainder of said second layer.

9. The envelope of claim 2, wherein:

said first flexible sheet material has a grain structure and is arranged so that the grain of said first layer is oriented in a transverse direction with respect to said envelope and the grain of said second layer is oriented in a longitudinal direction with respect to said envelope.

10. The envelope of claim 1, wherein:

said first and second walls are permeable to sterilizing gases and steam while being impervious to dust and bacteria, said second wall further being transparent.

confronting relationship therewith, said seal being in the l0 form of a relatively narrow band around three sided of the periphery of said envelope leaving one end thereof open;

said seal at the other end of said envelope being displaced inwardly from at least one comer to permit the confronting corners of said walls to be readily separated preparatory to opening said envelope;

said first and second walls are permeable to steam and sterilizing gases while being impervious to dust and bacteria. 

1. An envelope for enclosing and retaining articles before, during and after sterilization, comprising: a unitary first wall of first flexible sheet material comprising a first layer of said first material and a second layer of said first material, said layers being mechanically bonded together; and a second wall of second flexible sheet material being dimensionally similar to said first wall; said second wall being sealed to said first wall around three sides of the periphery thereof to form said envelope having one end open, said seal being in the form of a relatively narrow band.
 2. The envelope of claim 1 wherein: said second layer of said first flexible sheet material is thin compareD with said first layer and said second wall is arranged in facing relation with and sealed to said second layer.
 3. The envelope of claim 2, wherein: said seal at the other end of said envelope is displaced inwardly from at least one corner thereof to permit the confronting corners of said walls to be freely separated.
 4. The envelope of claim 1, wherein: said sealed areas of said envelope being capable of withstanding sterilization temperatures without deterioration of the seal quality.
 5. The envelope of claim 2, wherein: said first and second layers comprising said first wall are paper and said second wall is a thermoplastic film capable of being heat sealed to said first wall.
 6. The envelope of claim 4, wherein, said second wall is nylon film.
 7. The envelope of claim 3, wherein: the open end of said envelope may be heat sealed to close the interior of said envelope.
 8. The envelope of claim 7, wherein: said envelope may be opened by forcibly pulling said second wall from said first wall, wherein said second layer in the vicinity of said seal separates from said first layer and is ruptured from the remainder of said second layer.
 9. The envelope of claim 2, wherein: said first flexible sheet material has a grain structure and is arranged so that the grain of said first layer is oriented in a transverse direction with respect to said envelope and the grain of said second layer is oriented in a longitudinal direction with respect to said envelope.
 10. The envelope of claim 1, wherein: said first and second walls are permeable to sterilizing gases and steam while being impervious to dust and bacteria, said second wall further being transparent.
 11. An envelope for enclosing and retaining articles before, during and after sterilization, comprising: a flexible, unitary first wall comprising a first layer of relatively thick paper and a second layer of similar relatively thin paper, said layers being mechanically bonded together; and a flexible second wall of transparent thermoplastic film dimensionally similar to said first wall, said second wall being heat sealed to said second layer of said first wall in confronting relationship therewith, said seal being in the form of a relatively narrow band around three sided of the periphery of said envelope leaving one end thereof open; said seal at the other end of said envelope being displaced inwardly from at least one corner to permit the confronting corners of said walls to be readily separated preparatory to opening said envelope; said first and second walls are permeable to steam and sterilizing gases while being impervious to dust and bacteria. 